Electric switch construction



Oct. 5, 1937. H A. DOUGLAS- 2,095,177

lELECTRIC SWITCH CONSTRUCTION Filed May 31, 1954 5 /N VEN TOR 'HARRY A. DOUG-L65 v Patented Oct. 5, 1937 PATENT OFFICE ELECTRIC SWITCH CONSTRUCTION Harry A. Douglas, Bronson, Mich., assignor to Kingston Products Corporation, a corporation of Indiana Application May 31, 1934, serial No. '128,281

3 Claims.

This invention relates to improvements in electric switches and more particularly to a snap action switch of the rotating knob type to quickly make and break a circuit.

It is an object of this invention to provide a switch of this type which is compact, simple in construction and readily assembled.

With these and other objects in view, reference is made to the accompanying sheet of drawing which illustrates a preferred embodiment of this invention with the understanding that minor detail changes may be made Without departing from the scope thereof.

In the drawing Figure 1 is a View in central vertical sectionl of anembodiment of this invention, with parts illustrated in elevation. Y

Figure 2 isa similar view in section taken at right angles to Figure 1.

Figure 4 isa detail view in section taken von the line 4 4, Figure 1. f

Figure 5 is a detail Vtop'plan view ofthe oscillating operator, actuator and bracket, taken on l the line 5 5, Figure 3. '1 f Figure 6 is a View in reduced scale in section taken on the line 6 6, Figure 1.

As illustrated in Figures 1 2, and 3, the switching mechanism is enclosed in a cup-shaped metallic cylindrical casing I, having the bottom or end closure 2 provided with a central circular opening 3, with the closure wallV thereabout spun upward to form an annular flange 4 thereabout with an inverted cup-shaped cap 5 rotatively mounted thereon with the depending outer sides preferably scored or knurled, as shown.

The open end of the casing I is closed by a contact carrying disc 1 of insulating material which is held securely in position by a plurality of spaced-apart fingers 8, preferably three Yin number, forming integral extensions of the casing Wall which are passed through corresponding notches 9 in the peripheryof the disc 'I and then Vbent over the outer surface of the disc to hold the same firmly Vagainst the end of theV casing wall. The contact carrying disc I mounts two electric terminals I and I I, preferably of the snap terminal type disclosed in thisY applicants prior copending application, Serial No. 713,713, filed March 2, 1934, `adapted to be electrically connected to electric conductors, not shown, upon the outer side of the disc 'I. As shown each terminal includes a rectangular block having a 55 cylindrical extension which extensions are .pref- Figure 3 is a view in section taken on the line Y (CIL 200-68) erably reduced in diameter, as shown. When this type terminal is employed, it is desirable to provide the carrier disc 'I with circular apertures through which the reduced extremities of the terminals are passed and the metal of the end is then expanded or riveted upon the interior of the disc 'I to hold the terminals in place. The terminals I0 and Il are mounted on perpendicular radii of the disc at equal distances from the center.

The center of the contact carrying disc 1 is provided with an integral rectangular projection of insulating material I upon its inner surface having Vsides I2 parallel to the radii passing through the terminals I 0 and I I with the edge adjacent the terminal I0 joined to an upwardly extending angular surface I3 terminating in a central transverse projection I4; An electric contact I5 in the form of a metallic strip is connected to terminal I0, preferably by passingv the reduced cylindrical portion thereof through an aperture provided therefor in the end of said strip upon the outer side of the contact carryingV disc. The other end of the strip is then passed through the disc 1 to embrace the adjacent side and angular surface of the central projection I upon the inner side of the disc 'I with the upper surface of the strip terminating ush with the fiat top of the central transverse projection I4. The upper surface of the insulating projection leading from the flat top of the transverse portion III opposite the contact strip I5 is continued downwardly Atherefrom at an angle similar to that formed by the upper surface of said strip for a similar distance and then curved upwardly to form a stop I6, for a purpose hereinafter described. The expanded or riveted head of the terminal I0 is preferably received in a recess provided therefor upon the inner surface of the disc 1 to be wholly received below that surface, for `a purpose hereinafter described.

The switching mechanism is carried upon a U- shaped metallic bracket having a rectangular base I'I, with a central cut out portion I8, to receive the projection I of the disc 1, providing endportions I9 one of which extends over the Vcountersunk expanded end of the terminal I0 and having the sides of the base I1 provided with integral outstanding perforated ears 20 and 2I. The reduced cylindrical portion Aof the terminal II is passed through the apertured ear 20 with the end expanded or riveted upon the upper surface thereof, while the other ear 2I is secured to' the disc I by a rivet 22 passing through the ear @11d disc with the metal of the ends expanded or 55 riveted thereon. The inner side of the end portion I9 of the base extending over the terminal I is spaced apart from the contact I5 and the opposite end portion I9 is in engagement with the central projection I of the disc 1. The spaced apart end portion I9 is provided upon its inner side with an integral upwardly extending stop 23 bent back at an angle and spaced apart from the contact I to form a stop complementary to the stop I6 of the insulating projection I.

'I'he ear bearing sides of the base are extended upward to form two similar arms 24 perpendicular to the base I1 and equally spaced from the axis of the casing I with each side of each arm provided midway its height with outstanding integral fingers 25. The switching device for alternately continuing the circuit from the terminal I I to the contact I5 of the terminal I0 is mounted to oscillate upon a pivot 26 passing through apertures in the upper ends of the arms 24. The circuit making and breaking mechanism includes an oscillating actuator A caused to oscillate by a manually operable oscillating operator O.

The actuator A is mounted upon a pivot pin 26, in the arms 24 of the supporting bracket and includes two similar metallic actuating plates 21, adapted to receive the pivot pin 26 and depend therefrom in sliding engagement with the respective arms 24 of the supporting bracket and terminating short of the high point of the carrier disc projection surface I4 with a portion of the opposite longitudinal sides struck up at right angles to the main body to form right angular flanges 28A extending upward from the bottom leaving oppositely disposed similar outstanding arms 29 extending from the body of the plate, the longitudinal edges ofthe flanges 28 are adapted to engageV the similar edges of the corresponding flanges on the respective plates 21'. The actuator plates 21- are mounted upon the pivot pin 26 in similarlongitudinal elongated bearings 39 allowing a sliding longitudinal movement of the plates about the pin 26. The upper surfaces of the actuator arms 29 lie. in the same plane which passes slightly below the axis of the pivot pin 26 when the upper end of the bearing 39 is in contact with the upper surface of the pin 26. A spring housing 3l in the form of an inverted U is mount'- ed between the plates 21 and embraced by the flanges 28. The extremities of the sides of the housing are provided with transverse flanges 32' with the terminations thereof inclined upwardly to engage the outer sides of the oppositely disposed actuator flanges on each side of the housing and position thebase, or top, of the housing at a distance below the lower end of the actuator bearing 30. The housing 3l receives in sliding engagement therewith a detent 33 in the form of a rectangular casing closed at the lower end in a rounded nose 34 and open at the other end to receive a coil spring 35 bearing against the interior of the nose and top of the housing. When the actuator and operator have been assembled upon the supporting bracket the fingers of the bracket arms 24 are bent toward each other, as shown in Figure 3, to prevent the nose 34 when mounted on the disc 1 from riding over either of the stops I6 or 23.

The actuator A is caused to oscillate by the movement of an oscillating operator O. The oscillating operator O is preferably a strip of metal transversely curved on the arc of a circle to provide longitudinal depending sides which are centrally' extended to form parallel perforated ears 36 adapted to be received between the actuator plates 21 and receive the pivot pin. The body of the strip is centrally struck up to form similar oppositely disposed angular top surfaces 31 depending downwardly therefrom on each side of the center and the curved sides adjacent the ears 36 are struck out to form transverse curved eX- tensions or stops 38 which contact the upper surfaces of the actuator arm 29 when. the lower end of the bearings 36 of the actuator are in engagement with the under side of the pivot pin 2li,

A manual operator in the form of a disc 39 of insulating material having an axial extension 40 is rotatively mounted within the annular flange 4 of the casing closure 2 for cooperation with the oscillating operator O, and is centrally secured to the rotatable cap 5 by an axial screw 4I threaded at its lower end to a nut 42 received in a recess upon the under side of said disc 39 to draw the upper surface of the disc into rotative engagement with the under side of the closure 2. The under side ofthe disc is provided with preferably three depending cams 43 equally spaced apart and adapted, upon rotation of the disc 39 by the manual rotation of the cap 5, to ride over the rounded upper surfaces 31 of the oscillating operator to successively rotate the oscillating operator rst in one direction and then in the other.

Figures l and 2 illustrate the normal position of the various parts of the switch when a cam 43 has moved the operator to one end of its travel from which it is seen that the current continuing nose 34 of the detent 33 has engaged the contact strip I5 of the terminal I 9 and is maintained in contact therewith by the tension of the spring 35 holding the nose 34 against the stop 23 of the base I1 of the bracket which spring has bodily moved the actuator to slide over the pivot pin 26 to bring the lower end of the bearing 39 in resilient engagement with the under side of said pivot pin and the actuator arms 29 have engaged both stop surfaces 38 of the oscillating operator and the circuit is oompleted from terminal II to the terminal Il) through the bracket, the actuator, and current continuing nose 34 to contact strip I5, and the circuit is also closed by the nose 34 acting as a current continuing bridge from the stop 23 of the bracket and the angular surface of the strip I5 connected to the terminal IU.

When the cap 5 is manually rotated it imparts a movement to the oscillating operator O about its pivot 36 by a cam 43 riding over and depressing the adjacent upper surface 31 of the oscillating operator and, through Contact of the stop 38 engaged thereby with the adjacent actuator arm 29, bodily moves the actuator A in the direction of the engaged stop 23 of the base I1 until the upper end of the bearing engages the upper side of the pin 29, placing the detent spring under greater tension than normal. As the rotative movement of the operator continues, it imparts a rotative movement to the actuator about its upper bearing on the pivot 26 causing the detent nose 34 to travel over the upwardly inclined surface of the Contact I5 towards its high point, as shown in Figure 3, holding the contact with the terminal I0 closed under a slightly increasing tension of the spring 35 as the nose approaches the high point of the contact I5. During the rotative movement, the pivot pin 29 acts as the fulcrum of a bell crank lever with power being applied upon one arm by the operator stop 38 at the point of contact P between the oscillating operator end 38 and the actuator arm 29. During this movement, the

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the nose 34 approaches a Vright angle to the angular surfaces of the contact I5, the friction of the nose thereagainst is .minimized The movement of the nose 34 toward the high point of the carrier projection increases the tension of the spring 35 `so that just before the nose reaches thehighv poi'nt, the spring 35 bodily moves the actuator away from the contact I to bring Vthe lower end of its Ybearing 30 into engagement with the under side of the pin 26 with the nose 34 still heldin engagement with the contact I5, and during this movement causes the actuator A to rotate about the point P as a pivot. In other words, during the application of power at P, the bell crank lever rotates about the pivot 26 as a fulcrum, but as the'nose 34 approaches the high point of the'projection,

power is applied at the lower end of the other arm of the bell crank lever causing it to rotate about the `point P as a fulcrum, the elongated bearing 30 allowing sliding movement of the actuator about the fixed pivot 26. The movement imparted to the actuator 2'! by the stored up power in the spring 35 causes the nose 34 to snap over the high point I4 of the projection I and to quickly extend the nose 34 to engage the stop IG on the other end of the insulating projection I and thereby quickly oscillate the nose to f break engagement with the contact of termi- From the above, it is seen that as soon as the cap 5 has rotated the oscillating operator O suiliciently to shift the actuator A from the normal pivot 26 to its eccentric pivot P, the spring 35 automatically completes the oscillation to* snap the nose 34 out of engagement with the contact strip I5 and thereby break the circuit from terminal II to terminal Ill. Upon further rotation of the cap 5 inthe same direction another cam 43 is caused to ride over and depress the upper curved vsurface of the operator O brought in the path of travel of 'said cam and the above described operation of the parts quickly closes the said circuit.

As shown and described, the parts of this improved switching mechanism, excepting the-rotating operator 39 and the contact carrying disc, are all adapted to be formed of metal stampings, or machined parts, to be easily and quickly assembled. The operating parts are dependable as the spring 35 for imparting the snap movement is fullyV protected and the other parts are so constructed that theswitch may be operated thousands of times without any of the parts deteriorating or getting out of order.

Certain features, common to the present application and to applicantsV Patent 2,044,065, June 16, 1936, are claimed in the aforesaid patent, and certain other features common to the present application and to applicants ccp-ending Y application,-Serial Number 728,278, filed May 31,

1934, are claimed in the latter application.

What `I claim is: 1. An electric switch, comprising: a casing at the other end; cam means disposed in said casing and carried bysaid end wall and occupying a general plane at a fixed distance from said end wall; operating means, disposed on Vthe outside of said end wall constructed and arranged to operate said cam means; said operating means and said end wall being relatively so constructed V- having an end wall at one end and being open and arranged that said cam means is rotatable nism mounted on said base; said switch mechanism including an operating lever having portions extending in opposite directions from its ulcrum and swingable between limiting positions in a plane transverse to said base; and said cam means and said operating lever being so constructed and arranged that when said base is assembled with said open end of said case, said operating lever and said cam means are thereby brought into operative relation so that in either limitingY position of said lever said lever has one of its portions disposed in the general plane occupied by said cam means so that rotation of said cam means swings said operating means in said transverse plane.

2. An electric switch, comprising: a casing having an end wall at one end and being open at the other end; rotatable cam means disposed in said casing and carried by said end wall, said.

cam means including a plurality of axial projections providing circumferentially spaced cam surfaces occupying a general plane at a fixed distance from said end wall; operating means, disposed on the outside of said end wall constructed and arranged to cooperate said cam means; said operating means and said end Wall being relatively so constructed and arranged that said cam means is rotatable about a xed axis transverse to the general plane of said end wall; a base; switch mechanism mounted on said base; said switch mechanism` including an operating lever having portions extending in opposite directions from its fulcrum and swingable in a plane transverse to said base; and said cam means'and said operating lever being so constructed and arranged that when said base is assembled with said open end of said casing, said v operating lever and said cam means are thereby HARRY A. DOUGLAS. 

